Rev. Hale is one of the few dynamic characters in the play. By the time that the action in Act 3 has advanced, Hale has recognized the injustice of the court and the deception not just of Abigail but of all the girls. So, when Elizabeth is hauled into court from her jail cell in order to give her reason for firing Abigail, Hale is already firmly on the side of right--Proctor's, Frances Nurse's, and Giles Corey's side. He knows that what the court and girls are doing is grievous and indefensible and can no longer play a part in it.
When Mary Warren's testimony falls apart in the court, the last opportunity available to stop the girls' deception is seemingly John Proctor's confession that Abigail started the accusations to save herself and get back at his wife. Elizabeth's answer to the question of why she fired Abigail is all-important because it can provide a motive for Abigail's accusations. However, for once in her life, Elizabeth lies to spare her husband, and Rev. Hale's immediate reaction is that
" 'it is a natural lie to tell' " (Crucible, Act 3).
Hale believes that any good wife would tell such a lie in defense of her husband, and Elizabeth's motivation for telling the lie is to spare someone. In contrast, Abigail's motivation in being false is to hurt others. Hale despises Abigail's deceit because of the dishonor that it has brought to his God's name, his profession, and because of the horror it has spread throughout the town.